Peripheral Arterial Disease (PAD)

What is PAD?

The process that leads to the development of plaque in arteries of the body is called atherosclerosis. This is a complex biologic set of events with numerous contributing risk factors. The location of the plaque and its stability determines the type of symptoms and the risk of major complications. The plaque that arises in the arteries of the leg may cause a cramping pain when walking, but the same type of plaque arising in the arteries to the brain may result in stroke, while that arising in the heart may cause angina, heart attack or other fatal complications. The plaque has a complex composition. It is a fixed part of the arterial wall and there is no medication that “dissolves” it. When the plaque is extensive enough to impede blood flow symptoms develop. The degree to which these symptoms impair function and quality of life are taken into consideration in determining the best plan for treatment.

What are the symptoms?

Peripheral arterial disease (PAD) may occur in the arteries supplying blood to the legs. This could involve any part of the arteries from the level of the kidney to the ankle. One or both legs may be involved. The problem is divided into two categories. They are referred to as limb threatening and non limb threatening.

The symptom most commonly described is intermittent claudication. Cramping pain begins in the calf muscle and persists until the muscle is given a chance to rest. It will come on with walking and will be relieved by resting. Within minutes the individual will be able to walk again for a limited distance. The distance for onset of pain may vary if there is an incline and also with the pace of walking. In some cases if the arteries above the groin are involved there may be a sense of weakness of the leg, an aching in the buttock and or a sense that the leg may give out. Pain may be less pronounced than the claudication symptoms in the calf. Any of these symptoms combined with an absent or weak pulse in the leg should lead to further investigation.

Limb threatening ischemia is present when there is constant pain and burning in the toes (forefoot). It is increased when the foot is elevated and slightly better if the foot is down. If there are ulcers or areas of obvious gangrene then we consider this situation to be a threat to the health and survival of the leg. Without some form of intervention and correction of risk factors the limb will be lost (amputation).

Why does it develop?

Damage to the arterial wall creates an inflammation response that tries to repair the area. The cycle of damage and repair continues over time and the process leads to the plaque formation that eventually can plug the artery. The risk factors that are most clearly associated with this problem are Smoking, Diabetes, elevated cholesterol and lipids, genetic factors and increasing age. The problem progresses over a long period of time and if the risk factors are not modified or controlled it is far more likely that the individual will progress to a limb threatening situation.

What is the Treatment?

The key in all cases is to control the risk factors. Smoking cessation is an absolute must. This can be complemented by nicotine replacement and other medications such as Zyban and Champix. The latter two are helpful but can have side effects that need monitoring and are best used in a supervised program with your family doctor. For assistance with effective smoking cessation strategy you can check the website www.quitnow.ca

Aspirin 81 mg per day is also important. It provides significant protection against heart attack and stroke and helps to slow the progression of plaque development. The addition of “statin” type drugs (Lipitor, Crestor etc.) is also recommended even in patients with normal cholesterol. Clearly if cholesterol is elevated then a combined dietary and medication approach should be in place to bring the lipid values into an acceptable range

The management of Diabetes is critically important. Formal diabetic education should cover nutrition and medical management. Regular daily monitoring of blood glucose as well as Hemoglobin A1C (HbA1C) every three months is essential. The target for this value is 6.5. A careful foot exam every 6 months is also suggested for patients with diabetes to check for structural changes and possible neuropathy (damage to peripheral nerves that can alter or diminish sensation in the feet.)

Dietary and nutritional factors that may have a positive impact are:

Fish oil- the substitution of two meals a week in the form of fish rather than red meat can be protective. Daily supplementation of fish oil (omega-3 fatty acids) may also have a protective effect in combination with a sensible diet.

Soy protein- 25 gm per day recommended as part of a heart healthy diet by the American Heart Association to lower LDL cholesterol

Alcohol- the consumption of one or two drinks per day is protective but greater consumption is not. Other health problems mount with increasing consumption. At this point in time there is no clear evidence that one type of alcohol is superior to others in this protective effect.

Tea- only facts supported are that survivors of a heart attack who drank two cups of regular tea a day had a 44% lower mortality rate over the following 4 year period than those who did not drink tea.

What about exercise?

Exercise is capable of achieving significant functional improvement as measured by walking distance. Numerous studies have been analyzed and conclude that a period of 6 months (24 weeks) of supervised walking exercise for three hours per week to the point of near maximal pain will generate the best results. It has also been shown that upper limb exercise is beneficial. It has direct benefits on the heart but also helps to induce some of the changes mentioned above. A recent study indicated that pole striding or Nordic walking (similar to cross country skiing without the skis) is even better than conventional walking. In order to walk effectively it is important to carefully study the foot architecture and correct or compensate for any structural abnormality (flat feet, fallen arches) or ankle instability (over pronation).

Endovascular and open surgery

If the limitation caused by the PAD is severe (unable to walk a block or 100 meters) or if limb threatening ischemia is present we will explore the options for directly improving the circulation through either reopening the artery or bypassing the blockage. Depending on the location of the blockages and the severity of the problem, the best approach will be determined. In the larger arteries above the groin we are often able to use a technique of balloon angioplasty and possibly a stent to brace the artery open. In the legs, these techniques have proven less durable and so a bypass is more often necessary. The key is to select the best approach for each patient’s problem based on their overall risks and the anatomic distribution of the disease. (See the section on operations and outcomes).